Safety valve

Abstract

A safety valve includes a valve body comprising a central passage, internal threads at one end, and an externally threaded neck at the other end; a hollow spring operated poppet comprising an externally and internally threaded proximal portion secured to the internal threads, a smaller distal portion, and a central bore; a hollow sliding member in the passage urged by the poppet, the sliding member comprising a grooved rim at one end, a projection at the other end, and two opposite exhaust ports through the projection; and first and second seals for sealingly engaging the distal portion with the sliding member and engaging the sliding member with the passage respectively. In response to directing gas through the bore and the exhaust ports into the neck and pressure of the gas exceeds a preset limit, the gas pushes the sliding member toward the proximal portion.

1 . A safety valve comprising:
 a valve body ( 1 ) comprising a central passage ( 11 ), internal threads ( 12 ) at one end of the passage ( 11 ), and an externally threaded neck ( 13 ) projecting out of the other end of the passage ( 11 );   a hollow spring operated poppet ( 2 ) comprising an externally and internally threaded proximal portion ( 21 ) threadedly secured to the internal threads ( 12 ), a distal portion ( 22 ) having a diameter less than that of the proximal portion ( 21 ), and a central bore ( 23 );   a hollow sliding member ( 3 ) disposed in the passage ( 11 ) and urged by the poppet ( 2 ), the sliding member ( 3 ) comprising a grooved rim ( 31 ) at one end, a projection ( 33 ) at the other end, and two opposite exhaust ports ( 34 ) through the projection ( 33 );   first sealing means ( 2 A) for sealingly engaging the distal portion ( 22 ) with the sliding member ( 3 ); and   second sealing means ( 3 A) for sealingly engaging the sliding member ( 3 ) with the passage ( 11 ),   wherein in response to directing compressible fluid through the bore ( 23 ) and the exhaust ports ( 34 ) into the neck ( 13 ) and pressure of the compressible fluid exceeds a predetermined pressure value, the compressible fluid in the neck ( 13 ) pushes the sliding member ( 3 ) toward the proximal portion ( 21 ).